Reference is made to Bull. Chem. Soc., Japan, Vol.-40, P-1660 (1967) wherein nickel oxide has been used as a catalyst for the hydration of 3-cyanopyridine to nicotinamide. The drawbacks are that the catalytic activity was reported to be low and the yield of nicotinamide was also low. Reference is also made to U.S. Pat. No. 4,008,241 to Gelbein et al for the production of nicotinamide from 3-cyanopyridine by an aqueous ammonia solution. The reaction temperature was 90-150° C., the reaction time was 4-8 hours and the ammonia concentration was 3-8 molar. The maximum conversion of 3-cyanopyridine was about 70%. The hydrolysis was also effected in the presence of ammonium nicotinate in an amount sufficient to essentially eliminate production thereof to produce a hydrolysis effluent containing nicotinamide, ammonia, unconverted 3-cyanopyridine and ammonium nicotinate, at a nicotinamide selectivity of essentially 100%. Further, in this process unconverted 3-cyanopyridine and ammonia were separated from the product nicotinamide by a multi-step separation process which is not cost effective and is a very difficult procedure to obtain the pure product. These are the main drawbacks of the above process.
Prior art also discusses the hydration of nitrites to amides. The conversion of nitrites to amides has been achieved by both chemical and biological means. Japanese Patent 93-206579, August, 1993, H. Hirayama (To Showa Denko K.K., Japan), European Patent 85-306670, Sep., 19, 1985, S. Asano and J. Kitagawa (to Mitsui Toatsu Chemicals Inc.) describe the use of a modified Raney Nickel Catalyst for this reaction. WO 90/09988 A1, Sep., 17, 1990, of A. McKillop and D. Kemp. (to Interlex Chemicals, Ltd.) describes the use of alkali metal borates for this reaction. U.S. Pat. No. 2,471,518, May 31, 1949 (to Pyridium Company); U.S. Pat. No. 4,721,709, Dec. 6, 1988 (to Standard Oil Company); German Patent Application 2,517,054, Apr. 17, 1975, (to Degussa Company), discuss the hydrolysis of 3-cyanopyridine in presence of sodium hydroxide. The use of a magnesium oxide catalyst for this hydration reaction are discussed in Chemical Engineering Science, 35, 330, 1975, by C. B. Rossa and G. B. Smith. Alkaline hydrolysis of 3-cyanopyridine to nicotinamide of the Degussa process is one of the most important commercial processes adopted by some firms in India. However, this process has some disadvantages i.e., the yield of nicotinamide is not very high and the conversion of 3-cyanopyridine is about 99%. The reaction has been conducted at a higher reaction temperature with an appreciable alkali concentration. Nicotinic acid is also produced with nicotinamide in the above process.
British Patent 1,133,013; 1968, describes the catalytic hydration of nitriles by manganese dioxide. Manganese dioxide has been prepared by the Redox method using potassium permanganate and manganese sulphate in an alkaline medium. The hydration of 3-cyanopyridine has been conducted using a catalyst to 3-cyanopyridine mole ratio of 2.16:1, and the yield is only 79.28 mole %. The process i.e., conversion of 3-cyanopyridine to nicotinamide, is similar to the conversion of 4-cyanopyridine to isonicotinamide. Manganese dioxide has been prepared by the Redox method using potassium permanganate and manganese sulphate in an alkaline medium. The main drawbacks of the process are that (a) the yield of isonicotinamide is less (b) it is not eco-friendly and (c) the amount of catalyst per mole of the feed for conversion is quite high.